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Titrating polyelectrolytes - Variational calculations and Monte Carlo simulations

Jönsson, Bo LU ; Ullner, Magnus; Peterson, Carsten LU ; Sommelius, Ola LU and Söderberg, Bo LU (1996) In Journal of Physical Chemistry 100(1). p.409-417
Abstract

Variational methods are used to calculate structural and thermodynamical properties of a titrating polyelectrolyte in a discrete representation. In the variational treatment, the Coulomb potentials are emulated by harmonic repulsive forces between all monomers; the force constants are used as variational parameters. The accuracy of the variational approach is tested against Monte Carlo data. Excellent agreement is obtained for the end-to-end separation and the apparent dissociation constant for the unscreened Coulomb chain. The short-range screened Coulomb potential is more difficult to handle variationally, and its structural features are less well described, although the thermodynamic properties are predicted with the same accuracy as... (More)

Variational methods are used to calculate structural and thermodynamical properties of a titrating polyelectrolyte in a discrete representation. In the variational treatment, the Coulomb potentials are emulated by harmonic repulsive forces between all monomers; the force constants are used as variational parameters. The accuracy of the variational approach is tested against Monte Carlo data. Excellent agreement is obtained for the end-to-end separation and the apparent dissociation constant for the unscreened Coulomb chain. The short-range screened Coulomb potential is more difficult to handle variationally, and its structural features are less well described, although the thermodynamic properties are predicted with the same accuracy as for the unscreened chain. The number of variational parameters is on the order of N2, where N is the number of monomers, and the computational effort scales like N3. In addition, a simplified variational procedure with only two parameters is pursued, based on a rigid-rod approximation of the polymer. It gives surprisingly good accuracy for certain physical properties. © 1996 American Chemical Society.

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type
Contribution to journal
publication status
published
in
Journal of Physical Chemistry
volume
100
issue
1
pages
9 pages
publisher
The American Chemical Society
external identifiers
  • Scopus:0013080346
ISSN
0022-3654
language
English
LU publication?
yes
id
b7971377-b910-4cf8-9d86-de1759d40bc4
date added to LUP
2016-10-03 19:16:08
date last changed
2016-11-01 14:42:27
@misc{b7971377-b910-4cf8-9d86-de1759d40bc4,
  abstract     = {<p>Variational methods are used to calculate structural and thermodynamical properties of a titrating polyelectrolyte in a discrete representation. In the variational treatment, the Coulomb potentials are emulated by harmonic repulsive forces between all monomers; the force constants are used as variational parameters. The accuracy of the variational approach is tested against Monte Carlo data. Excellent agreement is obtained for the end-to-end separation and the apparent dissociation constant for the unscreened Coulomb chain. The short-range screened Coulomb potential is more difficult to handle variationally, and its structural features are less well described, although the thermodynamic properties are predicted with the same accuracy as for the unscreened chain. The number of variational parameters is on the order of N<sup>2</sup>, where N is the number of monomers, and the computational effort scales like N<sup>3</sup>. In addition, a simplified variational procedure with only two parameters is pursued, based on a rigid-rod approximation of the polymer. It gives surprisingly good accuracy for certain physical properties. © 1996 American Chemical Society.</p>},
  author       = {Jönsson, Bo and Ullner, Magnus and Peterson, Carsten and Sommelius, Ola and Söderberg, Bo},
  issn         = {0022-3654},
  language     = {eng},
  month        = {01},
  number       = {1},
  pages        = {409--417},
  publisher    = {ARRAY(0x8658fe8)},
  series       = {Journal of Physical Chemistry},
  title        = {Titrating polyelectrolytes - Variational calculations and Monte Carlo simulations},
  volume       = {100},
  year         = {1996},
}